Small Ball Research Articles

The Effect of Prolonged Sitting on Thoracic Spine Mobility among College Students

Background and aims: Sitting over a prolonged period not only creates physiological health problem and cardiovascular diseases, but also increases the risk of musculoskeletal disorders. The goal of this study is to determine whether there is a link between thoracic spine mobility and prolonged sitting, and the objectives are, to assess whether there is a connection between the length of time spent sitting and the mobility of the thoracic spine and examine the effect of extended sitting on the mobility of the thoracic spine. Methodology: The inclusion and exclusion criteria were checked on patients who were willing to participate in the study, they will provide an overview of the study before measuring thoracic mobility using methods such as the sitting rotation test (bar in front), in order to limit movement in participants lower extremities during thoracic rotation, a small ball was placed between their knees and a PVC bar with a tape marker at the halfway also used, which helps to fix the upper extremity. Using revised Oswestry to measure thoracic disability levels, the values were evaluated. Results: The statistical analysis showed that those who spend more time in sitting had limited thoracic rotation range of motion. Also, the questionnaire of thoracic pain showed pain and high disability index who spend more time in sitting and travelling. Conclusion: In people who spend more than 7 to 8 hours sitting, the study’s findings showed that their thoracic spine mobility was decreased. According to the questionnaire, people who spend a lot of time sitting and travelling during the course of a day as well as those who experience discomfort or restriction when performing ADLs had a high disability index for thoracic spine pain.

The Effect of Creative and Traditional Games on Motor Coordination and Creativity in Action and Movement in Girls 6 to 7 Years Old

Background and Aims Creative solutions are essential to success in sports, the development of talent, and the selection system, and it is important to be flourished in the early years. On the other hand, the play environment is one of the most effective environments in supporting the motor creativity of preschool children. This study aimed to investigate the effect of creative and traditional games on motor coordination and creativity in action and movement in girls aged 6 to 7 years. Methods The present quasi-experimental study is an applied study that was conducted with a pretest-posttest design. A total of 107 girls aged 6-7 years were selected by the available sampling method based on inclusion and exclusion criteria and divided into two creative and traditional games. Demographic questionnaire, thinking creatively in action and movement (TCAM) test, motor coordination test (The Körperkoordinations test für kinder [KTK]), and motor games were used. The practice protocol included creative movement games such as crab-style walking relief competition, bubble game, hungry wolf, play with small colored balls, balloon games, and traditional games. For the pretest and posttest, the TCAM and KTK tests were performed. Data were analyzed using combined factor analysis of variance with repeated measures and Bonferroni post hoc test using SPSS software, version 22. Results The results showed that the main effect of the evaluation steps was significant (P=0.001) for the motor coordination variable and was better in both groups posttest in the motor coordination test. The main effect of the group is significant (P=0.001), and the creative exercise group had better motor coordination in the posttest. The interaction effect of the group in the evaluation stages is significant (P=0.001). The average total score of creativity and components of fluidity, initiation, and imagination in the posttest was higher in the pretest, and the creative game group obtained higher scores in these components. Performing creative games had a more significant effect on children’s creativity, movement, and physical coordination than traditional games. Conclusion The children’s physical coordination and motor creativity increase with the practice of creative games. Children’s motor creativity skills, especially mental skills, and their originality and imagination are supported through play. It is better to use creative practice and games to develop children’s mental and motor skills during school physical education hours.

High-Temperature Hardness in Hypereutectoid Steels with Various Microstructures Measured by Using Small Ball Rebound Hardness Test

The temperature dependence of hardness in hypereutectoid steels with various microstructures was measured by using the small ball rebound hardness test, and the effect of carbon state on the high-temperature hardness was discussed. As-received and spheroidized cementite steels consisted of spheroidized cementite, graphite and ferrite matrix, and the volume fraction of graphite in the spheroidized cementite steel was larger than that in the as-received steel. Pearlite steel had ferrite and cementite lamellar structure without graphite. The characteristic hardening was detected above 700 K in all steels, suggesting that the solid solute carbon enhances the hardness even in hypereutectoid steels with high strength. The pearlite steel exhibited the highest hardness owing to the ferrite and cementite lamellar structure and no graphite. While the spheroidized cementite steel exhibited the lowest hardness, although the size of cementite was finer than that in the as-received steel. It was quantitatively demonstrated that the large volume fraction of graphite caused the low hardness in the spheroidized cementite steel.

Robust empirical risk minimization via Newton’s method

A new variant of Newton’s method for empirical risk minimization is studied, where at each iteration of the optimization algorithm, the gradient and Hessian of the objective function are replaced by robust estimators taken from existing literature on robust mean estimation for multivariate data. After proving a general theorem about the convergence of successive iterates to a small ball around the population-level minimizer, consequences of the theory in generalized linear models are studied when data are generated from Huber’s epsilon-contamination model and/or heavy-tailed distributions. An algorithm for obtaining robust Newton directions based on the conjugate gradient method is also proposed, which may be more appropriate for high-dimensional settings, and conjectures about the convergence of the resulting algorithm are offered. Compared to robust gradient descent, the proposed algorithm enjoys the faster rates of convergence for successive iterates often achieved by second-order algorithms for convex problems, i.e., quadratic convergence in a neighborhood of the optimum, with a stepsize that may be chosen adaptively via backtracking linesearch.

Keterampilan Dasar Melempar, Menangkap, Dan Memukul Bola Pada Siswa Kelas Iv SD Negeri Kebun Bunga 1 Banjarmasin

The purpose of this study was to find out how high the level of basic skills in throwing, catching, and hitting the ball in grade IV students of SD Negri 1 Kebun Bunga, Banjarmasin. Academic Year 2022/2023. The research method uses observation techniques and test techniques which are carried out practically, namely the practice of basic movement abilities with small ball games. Researchers observed children's activities in the learning process in cycles one and two. While the test results data obtained from tests conducted at the end of learning. The research procedure was carried out in accordance with the research put forward by (Widyatmoko, 2016) "The stages carried out in each research cycle include: planning stage, action stage, observing stage, and reflecting stage. These steps constitute a single action unit which is referred to as a cycle of action. The results of the research using observation techniques and practical test techniques. Get an increase in basic movement abilities. As for the increase in students' basic movement abilities with an average value of cycle I was 77.5 while the average value of cycle II was 87. The increase in the average value of cycle I to cycle II was 10.5. The benefits of this research for the general public as the development of insight into learning activities and for teachers as an alternative in the use of small ball games in physical education learning.

Generalized Singleton Bound and List-Decoding Reed–Solomon Codes Beyond the Johnson Radius

In this paper we take a combinatorial approach to the problem of list-decoding, which allows us to determine the precise relation (up to the exact constant) between the decoding radius, list size, and code rate. We prove a generalized Singleton bound for a given list size, and conjecture that the bound is tight for most Reed–Solomon (RS) codes over large enough finite fields. We also show that the conjecture holds true for list sizes 2 and 3, and as a by product show that most RS codes with a rate of at least 1/9 are list-decodable beyond the Johnson radius. Last, we give the first explicit construction in the literature of such RS codes. The main tools used in the proof are a new type of linear dependency between codewords of a code that are contained in a small Hamming ball, and a surprising connection between list-decoding and the notion of cycle space in graph theory. Both of them are new, and may be of independent interest.

Positive solutions for Kirchhoff equation in exterior domains with small Sobolev critical perturbation

ABSTRACT The paper concerns with the existence of positive solutions for the following Kirchhoff problem { − ( a + b ∫ Ω | ∇u | 2 d x ) Δu + u = | u | p − 2 u + ε | u | 4 u in Ω , u ∈ H 0 1 ( Ω ) , where a, b>0, 4<p<6, 0 $ ]]> ε > 0 is a parameter and Ω ⊂ R 3 is an exterior domain, that is, Ω is an unbounded domain with R 3 ∖Ω nonempty and bounded. After showing the nonexistence of ground state solutions, we prove the existence of one positive solution with higher energy when R 3 ∖Ω is contained in a small ball and 0 $ ]]> ε > 0 is sufficiently small. The novelty of this paper is that we extend the result obtained in Alves and de Freitas [Existence of a positive solution for a class of elliptic problems in exterior domains involving critical growth. Milan J Math. 2017;85:309–330] to nonlocal case and generalize the subcritical nonlinearity discussed in Chen and Liu [Positive solutions for Kirchhoff equation in exterior domains. J Math Phys. 2021;62:Article ID 041510] to small critical perturbation.

Minimax estimation of the mode of functional data

We give a definition of the mode of a probability distribution defined on an infinite-dimensional space and establish the minimax convergence rate. Therein, the existence of a probability density with respect to some abstract reference measure will not be required, while instead we use small ball probabilities to define the mode. The optimal rates of convergence are of logarithmic type under additional constraints on the small ball probabilities and entropy. We assume that the mode is contained in some totally bounded set and use covering methods to define a mode estimator and deduce strong consistency and rate optimality.

Lossy compression of general random variables

AbstractThis paper is concerned with the lossy compression of general random variables, specifically with rate-distortion theory and quantization of random variables taking values in general measurable spaces such as, e.g. manifolds and fractal sets. Manifold structures are prevalent in data science, e.g. in compressed sensing, machine learning, image processing and handwritten digit recognition. Fractal sets find application in image compression and in the modeling of Ethernet traffic. Our main contributions are bounds on the rate-distortion function and the quantization error. These bounds are very general and essentially only require the existence of reference measures satisfying certain regularity conditions in terms of small ball probabilities. To illustrate the wide applicability of our results, we particularize them to random variables taking values in (i) manifolds, namely, hyperspheres and Grassmannians and (ii) self-similar sets characterized by iterated function systems satisfying the weak separation property.

Volume comparison with respect to scalar curvature

In this article, we investigate the volume comparison with respect to scalar curvature. In particular, we show volume comparison holds for small geodesic balls of metrics near a V-static metric. For closed manifold, we prove the volume comparison for metrics near a strictly stable Einstein metric. As applications, we give a partial answer to a conjecture of Bray and recover a result of Besson, Courtois and Gallot, which partially confirms a conjecture of Schoen about closed hyperbolic manifold. Applying analogous techniques, we obtain a different proof of a local rigidity result due to Dai, Wang and Wei, which shows it admits no metric with positive scalar curvature near strictly stable Ricci-flat metrics.

Diagnosis and treatment of the otitis externa and media

Diagnosis and treatment of the otitis externa and media

The four-dimensional Yang–Mills partition function in the vicinity of the vacuum

The partition function of four-dimensional Euclidean, non-supersymmetric textrm{SU}(2) Yang–Mills theory is calculated in the perturbative and weak coupling regime, i.e., in a small open ball about the flat connection and when the gauge coupling constant acquires a small but finite value. The computation is based on various known inequalities, valid only in four dimensions, providing two-sided estimates for the exponentiated Yang–Mills action in terms of the L^2-norm of the derivative of the gauge potential only; these estimates then give rise to Gaußian-like infinite- dimensional formal integrals involving the Laplacian and hence can be computed via zeta-function and heat kernel techniques. It then turns out that these formal integrals give a sharp value for the partition function in the aforementioned perturbative and weak coupling regime of the theory. In the resulting expression for the partition function, the original classical value of the coupling constant is shifted to a smaller one which can be interpreted as the manifestation, in this approach, of a non-trivial beta -function and asymptotic freedom in pure non-Abelian gauge theories.

Description of Neochlorella semenenkoi gen. et. sp. nov. (Chlorophyta, Trebouxiophyceae), a Novel Chlorella-like Alga with High Biotechnological Potential

Despite many publications about Chlorella-like algae, their reliable and accurate identification is still difficult due to their simplicity and high phenotypic plasticity. The molecular approach has revolutionized our understanding of the diversity of ’small green balls’, and a natural classification of this group is currently being developed. This work is aimed at providing a detailed study of the phylogenetic position, morphology, ultrastructure, and physiology of the biotechnologically remarkable Chlorella-like strain IPPAS C-1210. Based on the SSU–ITS1–5.8S–ITS2 phylogeny, genetic distances, and the presence of compensatory base changes (CBCs) in ITS1 and conserved regions of ITS2 secondary structures, we describe a new genus, Neochlorella, with IPPAS C-1210 as the authentic strain of the type species, N. semenenkoi gen. and sp. nov. In addition, we justify the reassignment of the strain C. thermophila ITBB HTA 1–65 into N. thermophila comb. nov. The distinctive ultrastructural and physiological traits of the new species are discussed.

Adjustment-Free Long-Distributed-Cavity Laser Using Small Glass Ball Cat-Eye Retroreflector

We report an adjustment-free long-distributed-cavity laser using a small high-index glass ball cat-eye retroreflector as the receiver. When the glass ball cat-eye was rotated or off-axis moved, its working characteristics were studied via the single cat-eye structure and the double cat-eyes structure. With the single cat-eye structure and an incident pump power of 4.22 W, the end-pumped Nd: YVO <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\mathbf {4}}$ </tex-math></inline-formula> laser delivered 985 mW continuous-wave output at a working distance of 2.85 m, whose full rotation angle at half power was ±27°. In addition, with the double cat-eyes structure and the same incident pump power, the laser delivered 385 mW output at a working distance of 1.20 m, which had a full rotation angle of ±19° and a transverse displacement tolerance of ±21 mm. As far as we know, this is the first time that a ball-shaped cat-eye retroreflector is used to establish an adjustment-free long-distributed-cavity laser.

Design of New Fan-Shaped Combined Wear-Resistant Plate for Super Tonnage Spherical Bearing

In order to improve the bearing and wear resistance of the sector composite wear plate, a new sector composite wear plate is designed based on the finite element method. By establishing the finite element calculation models of integral, segmented small circle inlaid and new fan-shaped combined anti-wear plate ball bearings, the pressure bearing and wear resistance of three types of wear plates are analyzed, calculated and compared. The results show that the three types of wear plates can meet the pressure bearing capacity. The pressure bearing capacity of the new fan-shaped composite wear-resistant plate is similar to that of the integral type, which is superior to that of the segmented small circle inlaid type. Because of the advantages in structure, processing and installation of the new fan-shaped composite wear-resistant plate, it is particularly worth popularizing and applying in the super spherical bearing.

Dirichlet Sub-Laplacians on Homogeneous Carnot Groups: Spectral Properties, Asymptotics, and Heat Content

Abstract We consider sub-Laplacians in open bounded sets in a homogeneous Carnot group and study their spectral properties. We prove that these operators have a pure point spectrum and prove the existence of the spectral gap. In addition, we give applications to the small ball problem for a hypoelliptic Brownian motion and the large time behavior of the heat content in a regular domain.

Non-Destructive Eggshell Strength Assessment Using Hertz Contact Theory—Part II: Implementation and Validation

Eggshell strength is a critical quality factor for consumption eggs as it affects the probability of breakage in practice. In this study, a fast and low-cost methodology for the non-destructive determination of eggshell strength is presented. The method utilized a small steel ball to impact the egg and a microphone to analyse the impact characteristics. Hertz contact theory was applied to relate the measured impact characteristics to the local stiffness of the eggshell. Therefore, a total of 150 eggs were studied on which eight consecutive measurements per egg were taken around the equator at equidistant places. The results showed a strong correlation of 0.93 between the traditional static stiffness measured during quasi-static compression tests and the average stiffness obtained from the new methodology. This paves the way towards fast, low-cost and non-destructive in-line shell strength measurements to reduce the number of cracked eggs reaching the consumer.

Non-Destructive Eggshell Strength Assessment Using Hertz Contact Theory Part I: Theory and Applicability

In the egg industry, fast and highly reliable quality measurements are crucial. This study presents a novel method based on Hertz contact theory that allows for non-destructive determination of eggshell strength. The goal of the study was to evaluate the material strength (Young's Modulus) and structural strength (stiffness) of eggshells. To this end, an experimental setup was constructed to measure the collision of an eggshell with a small steel ball, which was recorded using a laser vibrometer. The study analyzed a sample of 120 eggs and found a correlation of 0.85 between the traditional static stiffness measured during quasi-static compression tests and the stiffness obtained from the Hertz contact theory. The results show that Hertz contact theory is valid for small steel spheres impacting eggshells, while a sensitivity analysis indicated that the most important factor in determining the strength of the eggshell is the contact duration between the egg and the impactor. These results open up the possibility of grading eggs based on their shell strength in a non-destructive manner.

On the Practical Exponential Stability in Mean Square of Stochastic Perturbed Systems Via a Lyapunov Approach

The Lyapunov method is one of the most effective methods to analyze the stability of stochastic differential equations (SDEs). Different authors analyzed the stability of SDEs based on Lyapunov techniques when the origin can be considered as an equilibrium point. When the origin is not necessarily an equilibrium point, it is still possible to analyze the asymptotic stability of solutions concerning a small neighborhood of the origin. The purpose is to study the asymptotic stability of a system whose solution behavior is a small ball of state space or close to it. Thus, all state trajectories are bounded and close to a sufficiently small neighborhood of the origin. In this sense, the limited boundedness of solutions of random systems, or the chance of convergence of solutions needs to be analyzed on a ball centered on the origin. This is the so called “Practical Stability”. In this article, we mainly investigate the practical uniform exponential stability in the mean square of stochastic linear time–invariant systems. In addition, we are developing the problem of stabilization of certain classes of perturbed stochastic systems. Our crucial techniques include Lyapunov techniques and generalized Gronwall inequalities. Lastly, we provide a numerical example to illustrate our theoretical findings.

On Semi-Global Exponential Stability Under Sampling for Locally Lipschitz Time-Delay Systems

In this article, the stability preservation problem for locally Lipschitz nonlinear time-delay systems, by emulation of continuous-time dynamic output feedback controllers, is studied. Sufficient Lyapunov-like conditions are provided such that, by suitably fast sampling, the Euler emulation of continuous-time dynamic output feedback controllers ensures the semiglobal exponential stability of the related sampled-data closed-loop system. If other emulation schemes than the Euler one are used, practical semiglobal exponential stability is guaranteed, with arbitrarily small final target ball, by suitably fast sampling. The intersampling system behavior, as well as time-varying sampling intervals, is taken into account. In the provided results, the delay-free case is included as a special case. The practical applicability of the provided results is shown through the study of a nonlinear chemical reactor system with recycle and a glucose–insulin system.